The furore surrounding Cherie Blair over her dealings with a convicted conman has again raised questions over press coverage of public figures' private lives.

Labour MP Clive Soley, who is a vigorous campaigner on privacy issues, has written an open letter to Paul Dacre, Editor of the Daily Mail, challenging what he calls the "contentious attitudes, values and behaviour" of the newspaper.

Clive Soley MP: "The basic story is small beer"

In the letter Mr Soley asks how people can be convinced that they ought to go into public life when their "family life can be invaded or trashed?".

And media watchdog the Press Complaints Commission (PCC) says it has written to Mrs Blair asking her if she wants to take the matter further.

Normally, people who feel their privacy has been breached will approach the PCC themselves, but a spokesperson told BBC News Online the commission could approach the parties involved "if there is a matter of significant public interest".

"The fact that she is married to the prime minister is neither here nor there."

Public interest

The privacy clause of the PCC's code of conduct states: Everyone is entitled to respect for his or her private and family life, home, health and correspondence. A publication will be expected to justify intrusions into any individual's private life without consent.

But this is tempered by the rules on public interest which means that journalists can run the story if, for example, it results in "Detecting or exposing crime or a serious misdemeanour" or "Preventing the public from being misled by some statement or action of an individual or organisation".

Several sections of the media say the reason they are concentrating on the story is to find out whether the Downing Street press office has misled journalists.

If it has, the reasoning goes, then how can the public trust the prime minister's spokesman on other issues?

'Wicked woman'

Mr Soley told BBC News Online that he accepted this was an important issue but he said that the Daily Mail was not treating the story in this light.

"The basis of their story from day one was: 'wife of the prime minister has some unusual friends, one of whom may have been trying to get money or influence on the back of her name'.

"Instead of feeling sorry for her, they run nine pages on what a wicked woman she is," he said.

"I think we - both politicians and journalists - have all got caught up in a feeding frenzy over what is really a minor story. The issue itself is small beer."

Complaints upheld

The Blairs have not made a complaint to the PCC about any of the current press coverage although they have been swift to act on privacy issues concerning their children in the past.

In January this year, the commission censured the Daily Telegraph and the Mail for reporting that the family's eldest son, Euan, was considering applying for a place at Oxford University.

The Sport was also rapped in 2000 for publishing a photograph of Euan, then 15, kissing a girl at a Christmas ball.

And in 1999 a complaint was upheld against the Mail on Sunday after it ran a story about Kathryn Blair being accepted at a particular secondary school when 13 other children were not.

The story was judged to be inaccurate and to have invaded the teenager's privacy.